Tension has been rising between Thailand and Cambodia following the killing of a Cambodian soldier in May during a brief exchange of gunfire at a disputed border area between the two Southeast Asian neighbours.
WHERE DOES THE DISPUTE ORIGINATE?
Thailand and Cambodia have for more than a century contested sovereignty at various undemarcated points along their 817 km (508 miles) land border, which was first mapped by France in 1907 when Cambodia was its colony. That map, which Thailand later contested, was based on an agreement that the border would be demarcated along the natural watershed line between the two countries.
In 2000, the two countries agreed to establish a Joint Border Commission to peacefully address overlapping claims, but little progress has been made towards settling disputes.
Claims over ownership of historical sites have raised nationalist tension between the two countries, notably in 2003 when rioters torched the Thai embassy and Thai businesses in Phnom Penh over an alleged remark by a Thai celebrity questioning jurisdiction over Cambodia's World Heritage-listed Angkor Wat temple.
WHAT WERE PREVIOUS FLASHPOINTS?
An 11th century Hindu temple called Preah Vihear, or Khao Phra Viharn in Thailand, has been at the heart of the dispute for decades, with both Bangkok and Phnom Penh claiming historical ownership. The International Court of Justice awarded the temple to Cambodia in 1962, but Thailand has continued to lay claim to the surrounding land.
Tension escalated in 2008 after Cambodia attempted to list the Preah Vihear temple as a UNESCO World Heritage site, leading to skirmishes over several years and at least a dozen deaths, including during a weeklong exchange of artillery in 2011.
Two years later, Cambodia sought interpretation of the 1962 verdict and the ICJ again ruled in its favour, saying the land around the temple was also part of Cambodia and ordering Thai troops to withdraw.
WHAT'S BEHIND RECENT TROUBLES?
Despite the historic rivalry, the current governments of Thailand and Cambodia enjoy warm ties, partly due to the close relationship between their influential former leaders, Thailand's Thaksin Shinawatra and Cambodia's Hun Sen, whose daughter and son respectively are now the respective prime ministers in their countries. Thaksin and Hun Sen also remain active in politics.
But nationalist sentiment has risen in Thailand after conservatives last year questioned the government's plan to negotiate with Cambodia to jointly explore energy resources in undemarcated maritime areas, warning such a move could risk Thailand losing the island of Koh Kood in the Gulf of Thailand.
Tensions also rose in February when a group of Cambodians escorted by troops sang their national anthem at another ancient Hindu temple that both countries claim, Ta Moan Thom, before being stopped by Thai soldiers.
The issue is a problem for Thai Prime Minister Paetongtarn Shinawatra, whose government is facing multiple challenges on the domestic front, including a stuttering economy facing steep U.S. tariffs.
Thailand's military, however, has ramped up the rhetoric with statements that have contrasted with the government's conciliatory tone, expressing readiness for a "high-level operation" if sovereignty comes under threat.
Paetongtarn later echoed the military's position but said a peaceful resolution of the disputes was Thailand's priority. The mixed messaging underlines the troubled history between the billionaire Shinawatra family and the royalist military, which toppled its governments in 2006 and 2014.
HOW IS THE ISSUE BEING RESOLVED?
After the May 28 clash, both countries quickly promised to ease tension, prevent more conflict and seek dialogue via their joint border commission at a meeting planned for June 14.
The neighbours have issued diplomatically worded statements committing to peace while vowing to protect sovereignty, but their militaries have been mobilising near the border, raising concerns about another flare-up.
Cambodia, meanwhile, said existing mechanisms were not working and it planned to refer disputes in four border areas to the ICJ to settle "unresolved and sensitive" issues that it said could escalate tensions.
Thailand has not recognised the ICJ's rulings on the row and wants to settle it bilaterally.
